Cause

The Oracle error, ORA-22901, indicates that the SQL statement is attempting a comparison of a nested table, VARRAY, or LOB attribute of an object type that was attempted in the absence of a MAP or ORDER method.

Solution or Workaround

When executing the SQL statement, remove the reference of the st_geometry attribute from the SELECT list or use the sde.st_astext operator to return the geometry in its well-known text representation, which can be compared by the specified operator.

Note:Because the sde.st_astext operator returns the well-known text as an Oracle CLOB data type, the output value must be converted to a character string using the Oracle TO_CHAR function.

The following example demonstrates how to execute a query with the union operator when comparing geometries.